Monitor Your Heart

Unexplained Fainting

Unexplained Fainting: What is it?

When blood pressure drops and not enough oxygen reaches the brain, there is a sudden loss of consciousness. What happens next is what is often called “fainting,” “passing out,” a “blackout” or “syncope” (pronounced sing ko pea). Most often, a fainting episode is brief and consciousness is regained in a few minutes, although there may be a period of confusion.

How common is fainting? As much as 50% of the US population may experience a fainting event during a lifetime.1 Fainting accounts for 1-3% of emergency department visits and 6% of hospital admissions in the US each year.1

Syncope affects all age groups. Fainting can occur in healthy people, but it also can signal a medical condition.

Symptoms, Causes and Risk Factors 

Learn about common symptoms, causes and risk factors for unexplained fainting.

Treatment Options 

How is unexplained fainting treated? Find out here.

Your Healthcare Team 

Your healthcare team may include different specialists with knowledge about unexplained fainting.

Your Diagnosis 

Your healthcare team will use information and tests to arrive at a diagnosis.


  1. Morag R, Brenner B. Syncope. Medscape. August 11, 2011. Accessed August 23, 2011. http://emedicine.medscape.com/article/811669-overview.